Electromagnetic shielding is sometimes required for the electronic components of printed circuit board, to prevent externally generated electromagnetic fields from influencing the components and/or to attenuate radiation of electromagnetic fields created by operation of the components. In many cases, the shielding can be accomplished by surrounding the affected components with a sheet metal hood or cover that is conductively coupled to a ground plane of the circuit board. In applications where it is sufficient to shield just one side of the circuit board, a one-piece sheet metal cover dimensioned slightly smaller than the circuit board is positioned on the circuit board and soldered in place. Soldering is used both to electrically couple the shield to the circuit board ground plane and to rigidly secure the shield to the circuit board. The soldering may be accomplished by providing the shield with tabs that extend into plated through-holes in the circuit board, and the circuit board may additionally be provided with a peripheral ground plane conductor trace that is engaged by and soldered to the shield. In applications that require shielding on both sides of the circuit board, a two-piece sheet metal shield may be used to surround the entire circuit board. See, for example, the U.S. Pat. No. 6,872,880 to King et al., assigned to the assignee of the present invention, where a circuit board is sandwiched between two shield halves that snap together with interlocking tabs to eliminate the requirement of soldering the shield to the circuit board. Due to the many manufacturing and re-work difficulties associated with soldering sheet metal shields to circuit boards, and the desire to limit the use of solder in circuit board manufacturing, it would be advantageous to devise a one-piece electromagnetic shield capable of being retained on a circuit board without the use of solder.